1. Field of the Invention
The present invention relates to an improvement of a removable cap attached, in an insertion manner, to a front-end portion of a writing instrument such as marking pens, markers, water-color ink ball point pens and the like so as to protect an ink-applying portion of the writing instrument from damage and also so as to prevent ink from evaporating from the writing instrument.
2. Description of the Prior Art
In general, removable caps attached to the writing instruments such as marking pens, markers and the like are made of resin material which is excellent in properties preventing ink from evaporating from the writing instruments. A conventional type of the removable caps of the writing instruments has a construction as shown in FIGS. 3 to 6, in which: a conventional removable cap 24 has a double-walled construction closed as its rear end and opened at its front end so as to provide an inner-cap portion 25 in an inner space 26 of the cap 24. When the cap 24 is attached to a front-end portion of a writing instrument, the inner space 26 of the cap 24 is hermetically sealed.
Consequently, the conventional removable cap of the writing instrument having the above construction is excellent in properties of preventing ink from evaporating from the wiring instruments and in properties of protecting the ink-applying portion of the writing instrument from damage, and therefore, there is no problem in writing use itself. However, since the conventional removable cap 24 having the above construction is completely closed at its rear end, there is a fear that the cap 24 can suffocate an if the infant swallows the cap 24 whole. Thus, it is apparent that the need exists for an improved removable cap which will prevent ink from evaporating from a writing instrument and protect an ink-applying portion of the writing instrument from damage without fear that the cap suffocate an infant's bronchi even if the infant swallows the cap whole.